<template>
  <!-- 商品分类导航 -->
  <div class="type-nav">
    <div class="container">
      <div @mouseleave="leaveIndex" @mouseenter="enterShow">
        <h2 class="all">全部商品分类</h2>
        <transition name="sort">
        <div class="sort" v-show="show">
          <div class="all-sort-list2" @click="goSearch">
            <div
              class="item"
              v-for="(c1, index) in categoryList"
              :key="c1.categoryId"
              :class="{ cur: currentIndex == index }"
            >
              <!-- 一级分类 -->
              <h3
                @mouseenter="changeIndex(index)"
              >
                <a 
                :data-categoryName='c1.categoryName'
                :data-category1Id='c1.categoryId'
                >{{ c1.categoryName }}</a>
              </h3>
              <!-- 二三级分类 -->
              <div
                class="item-list clearfix"
                :style="{ display: currentIndex == index ? 'block' : 'none' }"
              >
                <div
                  class="subitem"
                  v-for="c2 in c1.categoryChild"
                  :key="c2.categoryId"
                >
                  <dl class="fore">
                    <dt>
                      <a 
                      :data-categoryName='c2.categoryName'
                      :data-category2Id='c2.categoryId'
                      >{{ c2.categoryName }}</a>
                    </dt>
                    <dd>
                      <em v-for="c3 in c2.categoryChild" :key="c3.categoryId">
                        <a 
                        :data-categoryName='c3.categoryName'
                        :data-category3Id='c3.categoryId'
                        >{{ c3.categoryName }}</a>
                      </em>
                    </dd>
                  </dl>
                </div>
              </div>
            </div>
          </div>
        </div>
        </transition>
      </div>
      <nav class="nav">
        <a href="###">服装城</a>
        <a href="###">美妆馆</a>
        <a href="###">尚品汇超市</a>
        <a href="###">全球购</a>
        <a href="###">闪购</a>
        <a href="###">团购</a>
        <a href="###">有趣</a>
        <a href="###">秒杀</a>
      </nav>
    </div>
  </div>
</template>

<script>
import { mapState } from "vuex";
// 引用lodash防抖节流
import throttle from "lodash/throttle";

export default {
  name: "TypeNav",
  data() {
    return {
      currentIndex: -1,
      show: true
    };
  },
  methods: {
    // 鼠标进入促发事件  使用throttle方法进行防抖
    changeIndex: throttle(function (index) {
      this.currentIndex = index;
      //console.log(index);
    }, 100),
    enterShow() {
      if(this.$route.path !== '/home'){
        this.show = true
      }
    },
    leaveIndex(index) {
      this.currentIndex = -1;
      if(this.$route.path !== '/home'){
        this.show = false
      }
    },
    goSearch(event) {
      let element = event.target
      //获取促发当前事件的节点 dataset获取到节点的自定义属性或者属性值
      let {categoryname,category1id,category2id,category3id} = element.dataset
      //如果标签的身上有categoryname属性那一定是a标签
      if(categoryname) {
        let location = { name: "search" }
        let query = { categoryName: categoryname }
        // 判断一级分类标签 
        if(category1id){
          query.category1Id =  category1id
        }else if(category2id){
          query.category2Id =  category2id
        }else{
          query.category3Id =  category3id  
        }
        // 如果路由中有params参数,要一起传递出去
        if(this.$route.params) {
          location.params = this.$route.params
          location.query = query
          this.$router.push(location) 
        }
      }
    },

  },
  //组件挂在完毕,就可以发送请求
  mounted() {
    if(this.$route.path !== '/home'){
      this.show = false;
    }
  },
  computed: {
    ...mapState({
      // 对像写法右侧需要的是一个函数,当这个计算属性使用时,右侧函数会立即执行一次
      // 注入一个参数state,使用的即为大仓库中的数据
      categoryList: (state) => state.home.categoryList,
    }),
  },
};
</script>

<style lang="less" scoped>
.type-nav {
  border-bottom: 2px solid #e1251b;

  .container {
    width: 1200px;
    margin: 0 auto;
    display: flex;
    position: relative;

    .all {
      width: 210px;
      height: 45px;
      background-color: #e1251b;
      line-height: 45px;
      text-align: center;
      color: #fff;
      font-size: 14px;
      font-weight: bold;
    }

    .nav {
      a {
        height: 45px;
        margin: 0 22px;
        line-height: 45px;
        font-size: 16px;
        color: #333;
      }
    }

    .sort {
      position: absolute;
      left: 0;
      top: 45px;
      width: 210px;
      height: 461px;
      position: absolute;
      background: #fafafa;
      z-index: 999;

      .all-sort-list2 {
        .item {
          h3 {
            line-height: 28px;
            font-size: 14px;
            font-weight: 400;
            overflow: hidden;
            padding: 0 20px;
            margin: 0;
            a {
              color: #333;
            }
          }

          .item-list {
            display: none;
            position: absolute;
            width: 734px;
            min-height: 460px;
            background: #f7f7f7;
            left: 210px;
            border: 1px solid #ddd;
            top: 0;
            z-index: 9999 !important;

            .subitem {
              float: left;
              width: 650px;
              padding: 0 4px 0 8px;

              dl {
                border-top: 1px solid #eee;
                padding: 6px 0;
                overflow: hidden;
                zoom: 1;

                &.fore {
                  border-top: 0;
                }

                dt {
                  float: left;
                  width: 54px;
                  line-height: 22px;
                  text-align: right;
                  padding: 3px 6px 0 0;
                  font-weight: 700;
                }

                dd {
                  float: left;
                  width: 415px;
                  padding: 3px 0 0;
                  overflow: hidden;

                  em {
                    float: left;
                    height: 14px;
                    line-height: 14px;
                    padding: 0 8px;
                    margin-top: 5px;
                    border-left: 1px solid #ccc;
                  }
                }
              }
            }
          }

          /* &:hover {
            .item-list {
              display: block;
            }
          } */
        }
        .cur {
          background-color: rgb(171, 218, 250);
        }
      }
    }
    // 过度动画开始
    .sort-enter{
      height: 0px;
    }
    //结束
    .sort-enter-to{
      height: 461px;
    }
    //动画的速率,时间
    .sort-enter-active{
      transition: all .5s linear
    }
  }
}
</style>